Sorry, first post to the list, so forgive if I'm sounding like a newbie... How would one get link quality information to the upper layers other than via a MAC service? I can see inserting a shim-layer service to isolate upper layers form the different MACs which may be under it, so as to provide a consistent service interface. Of course you can only get what the MAC provides, but the shim layer and upper layer's can be designed to handle gracefully different MAC capabilities (at least consistently).
I'm asking with a bit of a bias here: I'm currently working on MAC enhancements for 802.15.4 (in task group "e" in 802.15), including a proposal for enhanced link assessment information from the MAC. So of course I'd suggest not ruling out some better link metrics in the 802.15.4 MAC at some point, although upper layers still need to deal with existing 802.15.4 devices. So the general thinking from upper layer uses is very interesting. Thanks -Ben ----- Original Message ----- From: "Eunsook "Eunah" Kim" <[EMAIL PROTECTED]> To: "Philip Levis" <[EMAIL PROTECTED]> Cc: <[EMAIL PROTECTED]>; <[email protected]> Sent: Wednesday, May 28, 2008 7:54 PM Subject: Re: [6lowpan] New charter for 6lowpan > Philip, > Thanks for the comment. LQI in the draft was mentioned for one > requirement, and it is given as just one of the examples for routing > matrics to utilize possible information to build up better routing > metrics for low power networks. If you think we shouldn't bond 6LoWPAN > to use MAC metrics, I'm okay with that. We can rule out it, but keep > doing the study about routing matrics. Thank you. > > -eunah > > On 5/29/08, Philip Levis <[EMAIL PROTECTED]> wrote: >> >> On May 28, 2008, at 1:04 AM, Eunsook Eunah Kim wrote: >> >> > Dear Philip, >> > >> > >> > > What happens when a new low power link layer emerges? Having N >> > > different solutions, each with their own details, which somehow need >> > > to be made to work well together, seems like a path of brittle and >> > > difficult to manage networks. Switches are good, to a point; there's >> > > a >> > > reason you have routers. >> > > >> > > >> > >> > We don't talk about solutions. We want to see if 6LoWPAN has special >> > routing requirements due to 802.15.4 specific or not. If route-over >> > solutions can be provided to fit the requirements of 6LoWPAN, I'm >> > happy. >> > >> >> Exactly: as soon as you start talking about things like LQI, you are >> coupling yourself not only to a specific link layer, but also a specific >> implementation of that link layer. In practice, many networks use the >> 802.15.4 link layer but not its MAC layer, as it has terrible energy >> properties. >> >> Phil >> > _______________________________________________ > 6lowpan mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/6lowpan > _______________________________________________ 6lowpan mailing list [email protected] https://www.ietf.org/mailman/listinfo/6lowpan
